This apparatus is directed to inspection equipment for observation of the interior of closed machinery. In particular, as it intended to be used in an atmosphere which runs the risk of explosion. As set forth in Baddorf, U.S. Pat. No. 2,028,430, a danger exists in placing a high voltage lamp in an explosive atmosphere (a fuel storage tank in that instance). That disclosure mentions placing a lamp in a vapor proof chamber. The later patent of Crampton (U.S. Pat. No. 2,437,458) sets forth an open light display on an inspection periscope having an optical system. The unobvious apparatus of this disclosure is a device which enables the interior inspection of closed machinery subject to the possibility of an explosive atmosphere. The present device comes in a form having relatively a narrow dimension with an elongate cylindrical shape, and is particularly able to be positioned in a potentially explosive atmosphere without risk of explosion. The device incorporates an optical system which has an external eye piece which provides a magnified view through the optical system. There is an external opening from the structure (in conjunction with a mirror) which directs the field of view along a specified azimuth. The device has an elongate cylinder housing and is therefore able to be inserted through a drilled hole and rotated for inspection in several directions. It incorporates a mirror directed for inspection in a given direction; in like fashion, a similar mirror set at a similar angle having a common azimuth enables illumination in the same direction. This mirror reflects light from a lamp in a closed housing.
The possibility arises that an explosion might occur. The lamp is electrically powered, and to this end, suitable electrical conductors are connected with the lamp. Even so, the lamp is able to be used safely because the appartus includes a nitrogen supply delivering nitrogen under pressure to the vicinity of the lamp to fill the closed and sealed chamber. This constitutes a nonexplosive atmosphere. In the unlikely event that a spark occurs around the electrical apparatus within the equipment, there is no explosion because the entire atmosphere near the lamp is nitrogen.
The periscope further utilizes a remote battery pack. The battery pack includes a closed and hermetically sealed housing. Suitable batteries and switch gear are protected in this housing. The nitrogen supply system is connected to this housing and thereby delivers nitrogen to the vicinity of the battery pack so that all this equipment is protected by a nonexplosive atmosphere. Accordingly, the entire system of equipment is protected and made safe from explosion or inadvertent electrical spark which might potentially trigger an explosion.
While the foregoing sets forth the problem in context of the application of this apparatus and mentions certain important features of the apparatus, a better understanding of the apparatus will be obtained on a review of the below written specification in conjunction with the drawings.